1. Field of the Invention
The present invention relates to aromatic polyamide polymers based on an amino-monomer containing two hexafluoro-isopropylidine linking groups or two 1-phenyl-2,2,2-trifluorethane linking groups, which polymers have improved physical, mechanical and chemical properties, and to a method for preparing such polymers.
2. Description of Related Art
Polyamide condensation products of a fluorine-containing diamine such as 2,2-bis(4-aminophenyl) hexafluoropropane (hereinafter referred to a 4,4'6F-Diamine) and the chlorocarbonyl derivatives of dibasic aromatic acids are known in the art and are described in U.S. Pat. No. 3,328,352.
Included in the polyamides prepared in accordance with this patent are the reaction products of 4,4'-6F-Diamine and the acid halide derivatives of isophthalic acid, terephthalic acid and 2,2-bis(4-carboxyphenyl) hexafluoropropane. These polymers are characterized as having good high temperature properties and are disclosed to be useful in the production of fibers and films.
One of the problems associated with such polymers is that they exhibit relatively poor flow properties which render them difficult to process, particularly to injection mold or to spin into fibers. These polymers are also relatively hydrophilic and tend to absorb moisture which can effect their clarity, heat stability, processability, mechanical and electrical properties.
Copending application Ser. No. 316,254 filed in the USPTO on Feb. 27, 1989 discloses polyamide-imide polymers based on the polymer condensation product of a mixture of trimellitoyl anhydride chloride and at least one diamine selected from the group consisting of 4,4'-bis[4-(aminophenoxyphenyl) hexafluoroisopropyl] diphenyl ether, 4,4'-bis [2-(4-aminophenyl) hexafluoroisopropyl] diphenyl ether and 4,4'-bis [2-(3-aminophenyl) hexafluoroisopropyl] diphenyl ether.
These amino monomers contain two hexafluoroisopropylidene linking groups and are referred to under the category of 12F-Diamines. The polyamide-imide polymers prepared according to the above mentioned application have outstanding flow properties, good thermal properties and good solubility in aprotic organic solvents.
Polyamides prepared from so called 12-F monomers are disclosed in Applicants copending applications Ser. No. 124,744 and Ser. No. 124,634 filed in the USPTO on Nov. 24, 1987, now U.S. Pat. Nos. 4,822,868 and 3,845,183 respectively. These polymers may be prepared by forming the polymer condensation product of an aromatic diamine and 4,4'-bis[2-(4-chlorocarbonylphenyl) hexafluoroisopropyl] diphenyl ether Ser. No. 124,744 or the polymer condensation product of a hydroxy substituted or alkoxy substituted 12F-Diamine such as 4,4'-bis[2-(3-amino-4-hydroxyphenyl) hexafluoroisopropyl] diphenyl ether and a dibasic acid chloride such as isophthaloyl chloride, terephthaloyl chloride or 4,4'-bis[2-(4-chlorocarbonylphenyl) hexafluoroisopropyl] diphenyl ether Ser. No. 124,634. The latter application also discloses the preparation of polybenzoxazole polymers by heat treating the alkoxy or hydroxy substituted polyamides.
Similarly, copending application Ser. No. 124,704 filed in the USPTO on Nov. 24, 1987, discloses polyamide polymers prepared by forming the polymer condensation produce of a 12F-Diamine such as 4,4'-bis[(4-aminophenoxyphenyl)hexafluoroisopropyl] diphenyl ether with one or more diacids or diacid halides. The polyimides are also characterized as having improved solubility in organic solvents, low dielectric constants, superior thermal and thermooxidative stability and improved processing characteristics.
All of the aforementioned patent applications and their disclosures are incorporate herein by reference.